Large network services providers may use multiple Domain Name System (DNS) servers hosting DNS services for their customers often use a anycast networking technique to provide multiple identical DNS servers or service hosts advertising a common IP address. The multiple identical DNS servers or service hosts may be across the country or across the world.
A router receiving a DNS request may use the anycast protocol to route the DNS request to the “least cost” DNS server or service host. The least cost server or service host may comprise the physically or topologically nearest server or service host, the various cost factors such as network congestion and the like may result in the selection of more distant servers or service hosts. Thus, the anycast protocol provides an extremely efficient and resilient mechanism for providing DNS services to client devices.
When a network services provider is troubleshooting service problems associated with a customer's client device (or client device problems associated with a particular service), it is often important to know which server is hosting the services associated with the client device. For example, the client device may be infected by malware which causes the client device to send DNS requests (or other service requests) to a DNS server (or other service host) not associated with the network services provider. Even if the client device is communicating with an appropriate DNS server or service host, the specific DNS server or service host is not known to the client device since each of the DNS servers or service hosts advertise the same address to the client device. Thus, information specifically identifying the DNS server or service host is generally not known to troubleshooting and/or service personnel, who are then forced to deduce which DNS server or service host is being used by the client device or might otherwise be associated with the service problem.